A Marine Corps CH-53E Super Stallion crashed Wednesday near the Barry M. Goldwater Range in Yuma, Ariz., but none of the five Marines aboard the helicopter were injured, according to a spokesman for the Corps’ Weapons and Tactics Instructors Course.

The helicopter, based at the 3rd Marine Aircraft Wing at Marine Corps Air Station Miramar, Calif., crashed about 1 p.m. Mountain time while flying a training mission in support of the course, said 1st Lt. Gabriel Adibe.

The extent of the helicopter’s damage has not yet been determined, Adibe said, and the cause of the crash is being investigated.

The Marine Corps’ CH-53E Super Stallions have had the most serious readiness issues of all Corps’ rotary- and fixed-wing aircraft. All 146 CH-53Es will eventually be refurbished, and the Corps plans to buy 200 new CH-53K King Stallions by 2029.

Although Marine aviation saw a spike of crashes toward the end of 2016, the first few months of this year have been relatively quiet. The last major incident was on Dec. 13, when an MV-22B Osprey from Marine Medium Tiltrotor Squadron 265 crashed in shallow water off Okinawa after its rotor struck a refueling line, according to the Naval Safety Center.

That same day, another Osprey’s landing gear failed, so it landed on reinforced cushions at Marine Corps Air Station Futenma.